1. Field of the Invention
The present invention relates to a perpendicular magnetic recording head which performs a recording action by applying a recording magnetic field perpendicularly to a recording medium plane.
2. Related Background Art
As is well-known, a perpendicular magnetic recording head includes a main magnetic pole layer and a return yoke layer which are laminated with a predetermined distance therebetween on a surface opposing a recording medium and are magnetically coupled to each other on the deeper side of the medium-opposing surface in the height direction, a magnetic gap layer interposed between the main magnetic pole layer and return yoke layer on the medium-opposing surface, and a coil layer inducing a recording magnetic field between the main magnetic pole layer and return yoke layer upon energization. The recording magnetic field induced between the main magnetic pole layer and return yoke layer perpendicularly enters a hard magnetic film of the recording medium from the front end face of the main magnetic pole layer and returns to the front end face of the main magnetic pole layer through a soft magnetic film of the recording medium. This performs magnetic recording at a part opposing the front end face of the main magnetic pole layer.
A so-called shielded pole structure has recently been proposed, in which the distance (gap distance) between the main magnetic pole layer and return yoke layer on the surface opposing the recording medium is set narrow, i.e., to about 50 nm, in order to suppress the divergence of magnetic fluxes directed from the main magnetic pole layer to the return yoke layer and realize magnetic recording with less bleeding. On the other hand, the size in the track width direction of the front end face of the main magnetic pole layer, i.e., recording track width size, has been becoming narrower as hard disk drives have been attaining higher recording densities.
In a perpendicular magnetic recording head having a narrowed track, how to suppress side fringing at the time of skewing where the head is driven in a state tilted with respect to a recording medium has become a problem.
As a method of suppressing side fringing at the time of skewing, it has been known to provide a magnetic shield layer for absorbing magnetic fluxes leaking from sides of the main magnetic pole layer in the vicinity of the main magnetic pole layer as described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2005-190518), for example. Patent Document 2 (Japanese Patent Application Laid-Open No. 2005-100520) and Patent Document 3 (Japanese Patent Application Laid-Open No. 2006-216098) also show such techniques.